Leopardess said:"They're not predators as they look, they're actually filter feeders and feed off plankton and algae mostly. They do feed off small inverts as well."
Actually, they are predators that mostly eat bugs and any small fish unlucky enough to travel to the surface. Them eating algae just doesn't make much sense since they only swim at the surface and have an upturned mouth -not a lot of algae floats by. And as for filtering, they keep their mouths closed and have a trapdoor style mouth....which isn't conducive, as far as I'm aware, to filter feeding.
As for the pH issue, I have to disagree. As long as they're properly acclimated any "normal" pH is fine. My water is not 6.5 in that tank (more like 7.1) and she's just fine).
If you do a search on this site for pantodon buchholzi you should find plenty of info.
I was talking about the violet goby, not the african butterfly fish.